Exhaust-muffler.



PATENTED JULY 18, 1905.

B. CRAWFORD; EXHAUST MUFFLER.'

APPLICATION FILED MAY 4, 1903.

NKTED STATE-sv BENJAMIN CRAWFORD, or AUC LAND, ,N w zEaL Nn ExHAusTinuFFLeRJ. I i i siencxrrcamon forming part of LettersPatent Nb. 794,92dated July 1 8, 90 n a l u'PatentedJ'uly is, 1905.

Application filed May 4,1903. "Serial No. 155,565.

To all,whom it may concern:

Be it known that I, BENJAMIN CRAWFORD, a 1 subject of the King of GreatBritain, residing at Auckland, in the Colony of New Zealand, haveinvented-a new and useful Exhaust-Muf-j Her; and I do hereby declare thefollowing to' be a full, clear, and exact description of the same. Y Y

This invention relates to means whereby the explosive sound caused bythe emission;

' of the exhaust from gas and other'explosive engines from theexhaust-pipe into the outer air may be silenced. Such sound is. causedby reason of the exploded gas emitting from the mouth of theexhaust-pipe and striking the atmosphere in a compact volume.

The principle upon which the present invention has been based consistsin receiving the exploded gas in a chamber that is provided with anumber of openings for its egress, the total aggregate area of suchopenings being equal to the cross-sectional area of the exhaustpipe. Thegas only-escapes from these openings after it has been caused to take aspiral passage through the chamber. The

effect of this temporary detention of the gas is to provide an elasticcushion, upon which the explosion from the exhaust-pipe will strike,being then divided up so as to pass through the outlet-holes in a numberof-streams.

-In describing the appliances devised reference will be made to theaccompanying sheet of drawings, in whichv 2 Figure 1- is across-section, and Fig. 2 a central vertical section on line 3 40fFig. 1. In the figures theexhaust-pipe a enters the outer end of achamber e, provided with a spirally-shaped plate f, extending across.its 1 width, the inner end. or center of is closed, so as to afford aspiralfpas sagefto theexploded gases that enter the outerje'ndfof thepassage from the exhaust-pipe. The sides'of the spiral are formed withapertures g at intervals therein, the aggregate areas of such aperturesbeing made equal to the cross-sectional area of the exhaust-pipe a. Inthis case the exploded gases discharged in masses will be forced throughthe spiral, so that a portion of them will be divided oil" and will passout through'the apertures as they pass cushion of air or gas will alwaysbe within the center of thespiral chamber, so'thatthe force of theexplosionwill be deadened."

What I claim as my invention, anddesire to secure by Letters Patent, is-

An exhaustmufiler comprlsing a pair of parallel plates and aspirally-arranged wall or plateexte'nding between said plates and form-In testimony whereof I havesigned' this specification 'inthe presence oftwo subscribing' witnesses, this 26th day of March, 1903.

BENJAMIN CRAWFORD,

i I Witnesses:

E.SALMOND, E. BURKE-SMITH.

